A280637 - OEIS

%I #7 Jan 07 2017 11:54:31

%S 1,2,5,1,8,8,10,5,11,10,2,5,10,8,17,10,14,11,10,11,5,10,17,8,19,14,20,

%T 10,20,14,10,17,8,10,14,11,19,11,14,10,8,17,19,14,20,10,11,5,10,8,8,

%U 10,14,11,19,11,14,10,17,17,10,14,20,19,20,14,19,17,17,19,14

%N Sum of the digits of n^2+1.

%C For all k, iterations k->a(k) will reach the {5, 8, 11} cycle. See the Mathematical Reflections.

%H Mathematical Reflections, <a href="https://www.awesomemath.org/wp-pdf-files/math-reflections/mr-2014-02/mr_1_2014_solutions.pdf">Solution to Problem S294</a>, Issue 2, 2014, p. 12.

%F a(n) = A007953(A002522(n)).

%o (PARI) a(n) = sumdigits(n^2+1)

%Y Cf. A002522, A007953.

%K nonn,base

%O 0,2

%A _Michel Marcus_, Jan 07 2017